Pump



H. P. TYLER May 18, 1965 PUMP 2 Sheets-Sheet 1 Filed Oct. 8, 1962 INVENTOR. a HgNRY P. TYLER. Wilma TIME ATTORNEY.

May 18, 1965 H. P. TYLER PUMP Filed Oct. 8, 1962 2 Sheets-Sheet 2 INVEN TOR.

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United States Patent 3,183,845 PUMP Henry Park Tyler, South Bend, Ind., assignor to The Bendix Corporation, South Bend, Ind., a corporation of Delaware Filed Oct. 8, 1962, Ser. No. 228,966 3 Claims. (Cl. 103162) The present invention relates to a dual rotor pump and more particularly to a pump providing a pulse free flow.

In the past pump discharge rates vary throughout the pumping cycle to produce pressure pulsations. To a fluid system these pulsations can create erratic operation. It is, therefore, a principal object of this invention to control pulsing delivery of a pump means.

It is also an object of this invention to increase pump discharge quantity while reducing pump size to keep surface speeds and loads close to those known to be satisfactory for a long life pump.

Still another object of this invention is to provide a dual rotor pump having means of indexing the relationship of the cylinders of one rotor to the cylinders of the other.

As may be readily appreciated by those skilled in the art, other objects and advantages will be observed from the following description of a preferred embodiment illustrated in the drawings in which:

FIGURE 1 is a view of my pump with the housing broken and sectioned to show the inner details of a dual rotor pump according to my invention.

. FIGURE 2 is a sectional plan view of the pump taken along line 2-2 of FIGURE 1; and

FIGURE 3 is a graphical plot of pulse pressure vs. time of a pump designed in accordance with my invention.

In more detail, I have shown my invention as being applied to axial piston type pumps. However, it is within the realm of possibility to utilize my inventive concept with other piston pumps.

In FIGURE 1 I show a. pump housing bearingly supporting a pair of rotors 12 and 14, as by bearings 16 and18 and shaft 20. Between the rotors I have placed a common cam means 22 supported by bearings 24 and 26 within respective bearing blocks 28 and 30. Thus, the cam means is stationary except for pivoting motion about a vertical axis 32 as explained hereinafter. A pair of port plates 34 are arranged between the rotors 12 and 14 and the housing 10 and are held by locating pins 36. These port plates are of a common variety heretofore utilized in axial pumps having a kidney shaped discharge passage 38 and a kidney shaped inlet passage 39. The discharge passages may be in the form of a plurality of drilled passages preceded by a pressure transition series of holds (not shown).

Behind the port plates 34 adjacent the discharge passages mentioned, I have provided ferrules 40 which are biased by a spring 42 towards the port plate 34. These ferrules may be termed leakage control ferrules, and they eliminate elfects of bearing alignment changes due to temperature and pressure changes during pump operation.

As seen in FIGURE 1, the rotors 12 and 14 are shown in block form for simplicity with two plungers 44 each operatively mounted therewith. The plungers 44 are connected to cam following shoes 46 by a ball socket type joint, as seen sectioned in FIGURE 2. The shoes 46 are in turn held against the surface of cam or swash plate 22 by auxiliary cam plates 48 which is biased into its holding position by springs 50 acting through spring retainers 52 and thrust bearings 54. The thrust bearings 54 serve as pivot bearings for the auxiliary cam plates 48 and are splined so as to be driven by the shaft 20 having appropriately matching splines 56.

. and replacing it on the shaft.

Patented May 18, 1965 "ice thrust ball 58 operative with a thrust block 60 and by a spring 62. The spring 62 forces a shaft end 64 outwardly against a thrust ring 66 and seal retainer 68. The ball 58 takes the thrust of spring 62 also.

The housing is preferably of a two part construction that is bolted together, as by bolts 70, and are appropriately formed with an inlet port 72, FIGURE 1, and an outlet port 74, FIGURE 2. The inlet and outlet ports are commonly communicated to the inlet and outlet passages by way of respective passages through the housing, one of which, a pump discharge passage 76, is shown in FIGURE 2. The inlet passage 78 does not appear as clearly in the sections taken to illustrate my invention. However, anyone skilled in the art would be assumed to know how one may connect respective ports of two pumps to provide a common inlet and discharge. A simple ferrule type seal 80 is provided to seal the passages where the casing ports are joined.

The rotors 12 and 14 are preferably constructed to have an equal number of cylinders 82 having a sleeve 84 of wear resistant material inserted therein along which pistons 44 sealingly reciprocate. The rotors 12 and 14 are splined so as to mate with the splines 56 of shaft 20 to be driven thereby. In one instance having a 9 cylinder rotor, I have provided a shaft with 16 splines and the rotor with 16, such that when starting from a nearly vertical spline, the third spline axis makes a angle with respect to the vertical spline axis. In this very same pump I have mounted one rotor to the spline such that the vertical spline axis intersects the longitudinal axis of one of the cylinders, and in so doing and with a nine cylinder rotor, this means that the second cylinder is but 40 from the cylinder whose axis is intersected by the vertical spline axis. As for the other rotor, it is mounted so that the vertical spline axis passes through the rotor halfway between two cylinders. Thus, the rotors have been oriented to provide cancelling pulsations, as appears hereinafter. In any event the angular relationship can be indexed by simply removing one of the rotors, partially rotating it,

If, for example, the re- 7 moved rotor is rotated so that the rotor is rotated through 45 the cylinders of this rotor when replaced on the shaft 20 will be 5 behind their original position and thus not exactly between the cylinders of the other rotor. Such a design allows one to index the rotor relationship with one another.

Therefore, assuming the mid positioning of cylinders of one rotor with respect to the other rotor, the common exhaust port for both rotors and the common inlet, the pulses of discharge flow from rotor 12 (see curve 86, FIGURE 3) are eliminated by the pulses of the discharge flow from rotor 14 (see curve 88, FIGURE 3) to provide a flow having a straight line characteristic (see line 90, FIGURE 3).

While it is not necessary to have a constant pressure or variable pressure delivery, I have shown my invention embodied in such a pump. More particularly, the cam or swash plate, as it may be termed is provided with a projection 92 to which a spring 94 is adapted to urge the swash plate to pivot on bearings 24 and 26 to a position where the pump delivers a maximum pressure or quantity flow. In order to vary the pump discharge, I provide a simple servometer 96 which is connected to a control by a port 98, or internally by a passage (not shown). This control, as may be appreciated by one skilled in the art, may be a simple valve mechanism subjected to inlet and/or case pressure on one side and discharge pressure on the other to cause a flow of fluid to the servomotor 96 whenever discharge pressure is high enough to unseat the valve. This would then assist a spring 100 in overcoming spring 94 to move the cam plate 22 clockwise, as viewed in FIGURE 2, lowering delivery pressure.

The foregoing description is offered not as limiting the invention but merely as a means of constructing a device in accordance with my invention. Therefore, I only propose to be limited by the appended claims.

I claim:

1. A fluid pressurizing apparatus comprising:

a housing;

a shaft with a plurality of splines in said housing;

a first fluid displacing unit having a central opening adapted to receive the splines of said shaft, said first fluid displacing unit having a plurality of first fluid displacing members which members are equidistantly positioned, said first fluid displacing members including a plurality of first cylinders and located on said shaft so that an axis of one of the cylinders and an axis of a spline of the shaft are so arranged to be in the same radial plane and substantially-parallel;

a second fluid displacing unit having a central opening adapted to receive the splines of said shaft, said second fluid displacing unit having a plurality of equidistantly spaced second fluid displacing members in-. cluding a plurality of second cylinders with an axis of one of the second cylinders angularly displaced from the axes of said spline which is in the same radial plane as the cylinder of said first cylinders with said axis of said one of said second cylinders substantially parallel to the axis of said first cylinders of said first fluid displacing unit and the splines of said shaft; and

common passages to severally connect an inlet means and an exhaust means of said first and second fluid displacing units.

2. A fluid pressurizing apparatus in accordance with claim 1 and further comprising:

a control means for commonly actuating said first and second fluid displacement means of said first and second fluid displacing units including,

a cam means centrally disposed between said first and second fluid displacing units, said cam means being pivotally mounted to said housing, and

a servomotor operatively connected to said cam means to move said cam means about said pivotal connection With said housing to adjust the amount of stroke imparted to said first and second fluid displacing members as said first and second fluid displacing units are rotated by said shaft which servomotor and cam means cooperate to simultaneously regulate the stroke to be equal in said first fluid displacing unit and said second fluid displacing unit.

3. A fluid pressurizing apparatus comprising:

a housing;

a shaft rotatably supported by said housing, said shaft having a plurality of splines with each third spline at an angle of 45 with each other third spline;

a first rotor adapted to be driven by said shaft, said first rotor including a plurality of equispaced cylinders with fluid pressurizing reciprocating members therein, said first rotor being arranged to have an axis of one of said cylinders and an axis of one of the splines so arranged to be in the same radial plane and substantially parallel;

a second rotor adapted to be driven by said shaft, said second rotor including a plurality of equispaced cylinders with fluid pressurizing reciprocating members therein, said second rotor being arranged to have an axis of one of said cylinders of said second rotor and said axis of said spline which is in the same radial plane as one cylinder of said first rotor are so arranged to be in a different radial plane and substantially parallel;

a nonrotatable control means operatively connected with said reciprocating members of both said first and second rotors to equalize magnitude of delivery of said rotors;

a pressure responsive means operatively connected to said control means to vary said magnitude; and

common passages to severally connect an inlet means and an exhaust means for said cylinders of said first and second rotors.

References Cited by the Examiner UNITED STATES PATENTS 2,639,673 5/53 Hadekel l03161 2,858,767 11/58 Smith 10349 2,910,008 10/59 Weisenback ,l03.-l62 3,022,738 2/62 Krute l03-49 LAURENCE v. EFNER, Primary Examiner. 

1. A FLUID PRESSURIZING APPARATUS COMPRISING: A HOUSING; A SHAFT WITH A PLURALITY OF SPLINES IN SAID HOUSING; A FIRST FLUID DISPLACING UNIT HAVING AN CENTRAL OPENING ADAPTED TO RECEIVE THE SPLINES OF SAID SHAFT, SAID FIRST FLUID DISPLACING UNIT HAVING A PLURALITY OF FIRST FLUID DISPLACING MEMBERS WHICH MEMBERS ARE EQUIDISTANTLY POSITIONED, SAID FIRST FLUID DISPLACING MEMBERS INCLUDING A PLURALITY OF FIRST CYLINDERS AND LOCATED ON SAID SHAFT SO THAT AN AXIS OF ONE OF THE CYLINDERS AND ON AXIS OF A SPLINE OF THE SHAFT ARE SO ARRANGED TO BE IN THE SAME RADIAL PLANE AND SUBSTANTIALLY PARALLEL; A SECOND FLUID DISPLACING UNIT HAVING A CENTRAL OPENING ADAPTED TO RECEIVE THE SPLINES OF SAID SHAFT, SAID SECOND FLUID DISPLACING UNIT HAVING A PLURALITY OF EQUIDISTANTLY SPACED SECOND FLUID DISPLACING MEMBERS INCLUDING A PLURALITY OF SECONDS CYLINDERS WITH AN AXIS OF ONE OF THE SECOND CYLINDERS ANGULARLY DISPLACED FROM THE AXES OF SAID SPLINE WHICH IS IN THE SAME RADIAL PLANE AS THE CYLINDER OF SAID FIRST CYLINDERS WITH SAID AXIS OF SAID ONE OF SAID SECOND CYLINDERS SUBSTANTIALLY PARALLEL TO THE AXIS OF SAID FIRST CYLINDERS OF SAID FIRST FLUID DISPLACING UNIT AND THE SPLINES OF SAID SHAFT; AND COMMON PASSAGES TO SEVERALLY CONNECT AN INLET MEANS AND AN EXHAUST MEANS OF SAID FIRST AND SECOND FLUID DISPLACING UNITS. 